Flexible single-crystal film and method of manufacturing the same

• US 20040217423A1
• Filed: 04/28/2004
• Published: 11/04/2004
• Est. Priority Date: 04/30/2003
• Status: Active Grant

• Current Assignee: Industry-Academic Cooperation Foundation Yonsei University, Industry-University Cooperation Foundation Hanyang University
• Original Assignee: Industry-Academic Cooperation Foundation Yonsei University
• Inventors: Park, Jea-Gun, Park, Jong-Wan
• Granted Patent: US 7,592,239 B2
• Time in Patent Office: Days
• US Class Current: 257/352
• CPC Class Codes: H01L 21/76254 with separation/delamination along an ion implanted layer, e.g. Smart-cut, Unibond
• CPC Class Codes: H01L 27/1214 comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
• CPC Class Codes: H01L 27/1266 the substrate on which the devices are formed not being the final device substrate, e.g. using a temporary substrate
• CPC Class Codes: H01L 29/78603 characterised by the insulating substrate or support H01L29/78657 takes precedence
• CPC Class Codes: H01L 31/18 Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof

Abstract

The present invention relates to a flexible single-crystal film and a method of manufacturing the same from a single-crystal wafer. That is, the present invention can manufacture a silicon-on-insulator (SOI) wafer comprising a base wafer, one or more buried insulator layers, and a single-crystal layer into a flexible single-crystal film with a desired thickness by employing various wafer thinning techniques. The method for manufacturing a flexible film comprises the steps of (i) providing a SOI wafer comprising a base wafer, one or more buried insulator layers on the base wafer, and a single-crystal layer on said one or more buried insulator layers, (ii) forming one or more protective insulator layers on said single-crystal layer, (iii) removing said base wafer, and (iv) removing one or more of the insulator layers.

Claims

1. A flexible film comprising a single-crystal layer which is manufactured from a single-crystal wafer.

4. The flexible film according to any one of claims 1 to 3, wherein said single-crystal layer comprises a silicon or a compound semiconductor.

5. The flexible film according to any one of claims 1 to 3, wherein the thickness of said single-crystal layer is within the range from several ten nanometers up to several ten micrometers.

2. A flexible film, comprising:

a flexible single-crystal layer manufactured from a single-crystal wafer; and

one or more flexible insulator layers.

6. The flexible film according to claim 2, wherein said one or more flexible insulator layers are formed on a surface of the single-crystal layer.

3. A flexible film, comprising:

a flexible single-crystal layer manufactured from a single-crystal wafer; and

a device layer formed on a surface of the single-crystal layer.

7. The flexible film according to claim 3, further comprising one or more flexible insulator layers on the other surface of said single-crystal layer.

8. The flexible film according to claim 3 or 7, further comprising one or more protective layers on the device layer.

9. A method for manufacturing a flexible film, comprising the steps of:

providing a SOI wafer comprising a base wafer, one or more buried insulator layers on the base wafer, and a single-crystal layer on said one or more buried insulator layers;

forming one or more protective insulator layers on said single-crystal layer;

removing said base wafer; and

removing one or more of the insulator layers.

10. The method according to claim 9, wherein said step of providing the SOI wafer comprises the steps of:

providing the base wafer and a bonding wafer;

forming said one or more buried insulator layers on said base wafer;

implanting hydrogen ions into said bonding wafer;

bonding said base wafer and said bonding wafer;

cleaving said bonding wafer; and

etching the cleaved surface of said bonding wafer to manufacture the SOI wafer wherein the single-crystal layer is formed on the buried insulator layers of the base wafer.

11. The method according to claim 10, wherein said step of forming said one or more buried insulator layers on said base wafer comprises the steps of:

forming a nitride film on said base wafer; and

forming an oxide film on said nitride film.

12. The method according to claim 10 or 11, further comprising the step of cleaning said base wafer and said bonding wafer before bonding them.

13. The method according to any one of claims 9 to 11, wherein said step of removing said base wafer comprises the step of removing the base wafer by wet etching it.

14. The method according to claim 13, wherein KOH is used in wet etching said base wafer.

15. The method according to any one of claims 9 to 11, wherein said step of forming said one or more protective insulator layers on said single-crystal layer comprises the steps of:

forming an oxide film on said single-crystal layer; and

forming a nitride film on said oxide film.

16. The method according to any one of claims 9 to 11, wherein said step of removing one or more of the insulator layers comprises the step of removing all of the insulator layers by wet etching them with HF.

17. The method according to any one of claims 9 to 11, wherein said step of removing one or more of the insulator layers comprises the step of removing either said one or more buried insulator layers or said one or more protective insulator layers on the single-crystal layer by wet etching them with HF.

18. The method according to claim 15, wherein said step of removing said base wafer comprises the step of removing the base wafer by wet etching it.

19. The method according to claim 18, wherein KOH is used in wet etching said base wafer.

20. The method according to claim 18, wherein said step of removing one or more of the insulator layers comprises the step of removing all of the insulator layers by wet etching them with HF.

21. The method according to any one of claims 9 to 11, wherein said step of removing said base wafer comprises the steps of:

grinding the base wafer to a desired thickness;

removing the remaining base wafer after grinding by wet etching it.

22. The method according to claim 21, wherein KOH is used in wet etching said base wafer.

23. The method according to claim 21, wherein said step of removing said base wafer further comprises the steps of:

coating wax on the protective insulator layer and bonding said SOI wafer and a supporting wafer before grinding the base wafer; and

removing the supporting wafer after grinding the base wafer.

24. The method according to claim 21, wherein said step of removing one or more of the insulator layers comprises the step of removing all of the protective and buried insulator layers by wet etching them with HF.

25. The method according to claim 21, wherein said step of removing one or more of the insulator layers comprises the step of removing either said one or more buried insulator layers or said one or more protective insulator layers on the single-crystal layer by wet etching them with HF.

55. A flexible film manufactured by the method according to any one of claims 9 to 11, 26 to 29, 34 to 39, and 47 to 51.

26. A method for manufacturing a flexible film, comprising the steps of:

providing a SOI wafer comprising a base wafer, one or more insulator layers on the base wafer, and a single-crystal layer on said one or more insulator layers;

holding the SOI wafer with a jig to expose the lower surface of the base wafer; and

removing said base wafer by etching it.

27. The method according to claim 26, wherein said step of holding the SOI wafer comprises the step of holding the edges of the SOI wafer with the jig to expose the entire lower surface of the base wafer.

28. The method according to claim 26, wherein said step of holding the SOI wafer comprises the step of holding the peripheral portion of the SOI wafer with the jig to expose a portion of the lower surface of the base wafer.

29. The method according to claim 28, wherein said step of removing said base wafer comprises the step of cutting the peripheral portion which is held by the jig.

30. The method according to any one of claims 26 to 29, wherein said step of removing said base wafer comprises the step of wet etching it.

31. The method according to claim 30, wherein KOH is used in wet etching said base wafer.

32. The method according to claim 30, further comprising the step of removing one or more of the insulator layers by wet etching them with HF.

33. The method according to claim 32, wherein said step of removing one or more of the insulator layers by wet etching them with HF comprises the step of dipping the SOI wafer with the jig detached in an etching solution.

34. A method for manufacturing a flexible film, comprising the steps of:

providing a SOI wafer comprising a base wafer, one or more buried insulator layers on the base wafer, and a single-crystal layer on said one or more buried insulator layers;

bonding a supporting wafer to said single-crystal layer of said SOI wafer; and

removing said base wafer and said supporting wafer.

35. The method according to claim 34, wherein said step of removing said base wafer comprises the steps of grinding said base wafer to a predetermined thickness, removing said supporting wafer, holding the SOI wafer with a jig to expose the lower surface of the remaining base wafer after grinding, and removing the remaining base wafer by wet etching it.

36. The method according to claim 34, wherein said step of removing said base wafer comprises the steps of grinding said base wafer to a predetermined thickness, holding the SOI wafer with a jig to expose the lower surface of the remaining base wafer after grinding, removing the remaining base wafer by wet etching it, and removing said supporting wafer.

40. The method according to any one of claims 35 to 39, wherein said step of holding the SOI wafer with the jig comprises the step of holding the edges of the SOI wafer with the jig to expose the entire lower surface of the base wafer.

41. The method according to any one of claims 35 to 39, wherein said step of holding the SOI wafer with the jig comprises the step of holding the peripheral portion of the SOI wafer with the jig to expose a portion of the lower surface of the base wafer, and further comprising the step of cutting the peripheral portion which is held by the jig after wet etching the portion of said base wafer after grinding.

42. The method according to any one of claims 34 to 39, further comprising the step of removing said one or more buried insulator layers after removing said base wafer.

43. The method according to any one of claims 34 to 36, further comprising the step of forming one or more protective insulator layers on said single-crystal layer before bonding a supporting wafer to said single-crystal layer of said SOI wafer.

44. The method according to any one of claims 34 to 36, wherein the step of bonding a supporting wafer to said single-crystal layer of said SOI wafer comprises the steps of coating wax on said single-crystal layer of said SOI wafer and bonding a supporting wafer to said single-crystal layer of said SOI wafer.

45. The method according to claim 43, wherein the step of bonding the supporting wafer to said single-crystal layer of said SOI wafer comprises the steps of coating wax on the protective insulator layer and bonding said SOI wafer and a supporting wafer before grinding the base wafer;

and further comprising the step of removing said one or more buried insulator layers and/or said one or more protective insulator layers after removing said base wafer and said supporting wafer.

46. The method according to any one of claims 35 to 39, wherein KOH is used in wet etching said base wafer.

37. A method for manufacturing a flexible film, comprising the steps of:

providing a SOI wafer comprising a base wafer, one or more buried insulator layers on the base wafer, and a single-crystal layer on said one or more buried insulator layers;

grinding said base wafer to a predetermined thickness;

holding the SOI wafer with a jig to expose the lower surface of the remaining base wafer after grinding; and

removing the remaining base wafer by wet etching it.

38. The method according to claim 37, further comprising the step of forming one or more protective insulator layers on said single-crystal layer before grinding said base wafer, wherein the remaining base wafer is above 150 μ

m in thickness.

39. The method according to claim 38, further comprising the step of removing said one or more buried insulator layers and/or said one or more protective insulator layers after removing said base wafer.

47. A method for manufacturing a flexible film, comprising the steps of:

providing a SOI wafer comprising a base wafer, one or more insulator layers on the base wafer, and a single-crystal layer on said one or more insulator layers;

forming one or more device layers by manufacturing electronic devices on the single-crystal layer;

forming a protective film for the devices on the device layer; and

removing said base wafer.

48. The method according to claim 47, wherein said step of removing said base wafer comprises the step of wet etching the base wafer.

49. The method according to claim 47, wherein said step of removing said base wafer comprising the steps of

grinding the base wafer to a desired thickness;

and

removing the remaining base wafer after grinding by wet etching it.

50. The method according to claim 47, wherein said step of removing said base wafer comprises the steps of:

holding the SOI wafer with a jig to expose the lower surface of the base wafer; and

removing the base wafer by wet etching it.

51. The method according to claim 47, wherein said step of removing said base wafer comprises the steps of:

grinding the base wafer to a desired thickness;

holding the SOI wafer with a jig to expose the lower surface of the base wafer; and

removing the base wafer by wet etching it.

52. The method according to any one of claims 48 to 51, wherein KOH is used in wet etching said base wafer.

53. The method according to any one of claims 47 to 51, further comprising the step of removing said one or more insulator layers by wet etching them with HF.

54. The method according to any one of claims 47 to 51, wherein said step of forming the device layer by manufacturing the electronic devices on the single-crystal layer comprises the step of using a semiconductor manufacturing process.

56. A jig used in etching a wafer comprising:

a lower plate;

an upper plate having one or more through holes; and

fixtures for joining the lower and upper plates together,

wherein the wafer is positioned between said lower plate and said upper plate, the portion of the wafer to be etched is exposed through said one or more through holes, the wafer and said one or more through holes are sealed, and an etching solution is supplied through said one or more through holes.

57. The jig according to claim 56, wherein said upper plate is provided with a bath for containing the etching solution, and said bath is communicated with said one or more through holes.

58. The jig according to claim 57, wherein a heater and a thermometer are provided in the bath.